Here at Major League Soccer, we characterize it as a player “who played at least one minute in each and every season in league history.” And as we all know, they’re a dying breed.

At the end of last season, there were only three left. But then Jesse Marsch retired and Steve Ralston left for second-division AC St. Louis before hanging up his cleats two months ago.

That left only Jaime Moreno. So it was big news when D.C. United announced a couple weeks ago that the last remaining “MLS original” would not be back at RFK Stadium next season.

Not to take anything away from Moreno, who has been a class act in each of his 15 seasons of MLS, still holds the all-time scoring record with 132 goals (for now) and has been a near-perfect ambassador for the success of the league.

But MLS original? Semantics. The league is full of veterans who have been around since Day 1. Brian McBride, Ramiro Corrales, Frankie Hejduk, Eddie Lewis and Zach Thornton all were on MLS squads during that inaugural season. And all of them are still going strong.

They’re just not MLS originals. At least not by league standards.

“We’re being punished for going to Europe, I guess,” chuckled Hejduk this week.

And you can’t blame him. The fact that each of these five grizzled veterans decided to give it a go in the Old World actually hurt their standing – at least as far as the “MLS original” goes.

And that’s the ironic thing. The guys who went to go slog it out with the big boys during MLS’ infancy, the guys who had to scrap and fight every day just to prove a daring Yank belonged – well, there’s more of them left now than the guys who stuck around.

It just happens to be the fans’ divine reward that they came back after differing experiences away from the league. Hejduk and Lewis departed MLS after a few seasons with Tampa Bay and San Jose, respectively.

Hejduk went on to help Bayer Leverkusen reach the 1999 Champions League final before eventually finding his way back to Columbus in 2003. Lewis worked his tail off for eight years, mostly in the English second division, for Fulham, Preston North End, Leeds United and Derby County. He had mixed results at two World Cups, and eventually found his way back to his hometown LA Galaxy in 2008.

McBride, of course, had arguably the greatest success of any American player overseas. His four seasons at Fulham won him the adoration of the Craven Cottage faithful. His tireless work rate, complete disregard for his own face and more than 150 goals eventually earned him the captain’s armband. No wonder it was something of a coup that his hometown Chicago Fire landed his signature two summers ago.

OK, so we’re talking three guys who all started in Major League Soccer, yet each spent more than five seasons abroad. Maybe they don’t deserve to be part of some elite club of MLS lifers. But doesn’t it seem a little punitive for the other two?

Corrales played less than three seasons in Norway after time with Columbus, San Jose, Miami and the MetroStars. Now he’s back in his native Northern California as Earthquakes captain, and it’s hard to imagine he was ever elsewhere.

Then there’s Thornton. Big Z has played so long, he was Tony Meola’s backup during his first two seasons with the MetroStars. His 15-year career has also seen him man the nets for Chicago, Colorado and, now, Chivas USA.

That’s approaching 300 appearances in every season MLS has ever had ... except for 2004. Thornton took a chance on a six-month contract with Benfica that ultimately didn’t yield a single appearance. And that’s what precludes him from the “original” tag. Six lousy months.

But not a single one of these players is bitter. All five know each other quite well – not just from their years of MLS service, but dating back to time spent in the US youth set-up and various senior national-team stints. But they don’t sit around complaining that they don’t get their just desserts from the league.

“If anything,” joked Thornton, who turns 37 next month, “we look at each other and say, ‘Man we’re getting old.’”

It’s a funny thing. For as much gratitude as we all owe to Moreno – who is truly, at this point, the last of his kind – we almost owe a bigger debt to the 96ers. They all got their starts in MLS, and helped get it off the ground when it could have crashed and burned like so many failed professional American leagues before it. And yet they all found their way back home after their great adventures.

“This is a really good league,” Hejduk said. “Some of the [American] guys who had played overseas who hadn’t played in MLS didn’t know what to expect when they came home. They expected it to be chill and lackadaisical.

“It’s not. It’s tough. You can see that even with guys like Rafa Márquez and [Thierry] Henry – they see it’s not easy.”

No, MLS isn’t yet in the public eye to the magnitude of the NFL, the NBA or Major League Baseball. But it is a financially sound, established league with enough money and support to survive – and it only gets bigger every year.

What an amazing gift it is that so many of the 96ers are still around – and still playing at a fairly high level, even though each is approaching 40. (Former teen sensation Corrales, only 33, is the lone exception.)

“I feel like I’m 20 years old, to be honest,” said the 36-year-old Hejduk. “It’s not until I look around and go, “Wow, dude, I’m the second-oldest guy on the team,’ that I realize that.”

Corrales, Hejduk and Thornton will certainly return in 2011. Lewis, most likely. McBride, you never know when he’ll call it a day. That means every second these guys are still on an MLS pitch at the same time is like peering back into league history.

You tell me that’s not deserving of “original” status. When the 96ers are gone, the term will matter little. What they did for the league, well, that’s a legacy that’ll last longer than your favorite pair of 501s.

Jonah Freedman is the managing editor of MLSsoccer.com. “The Throw-In” appears every Thursday.